Collective effects enhancing power and efficiency

Abstract

Energy conversion is most efficient for micro or nano machines with tight coupling between input and output power. To reach meaningful amounts of power, ensembles of N such machines must be considered. We use a model system to demonstrate that interactions between N tightly coupled nanomachines can enhance the power output per machine. Furthermore, while interactions break tight coupling and thus lower efficiency in finite ensembles, the macroscopic limit (N → ∞) restores it and enhances both the efficiency and the output power per nanomachine.

Collective performance of a finite-time quantum Otto cycle

“…Our results in this Section complement the previously reported ones on performance enhancement due to collective effects in quantum transport [44][45][46] or in models of quantum batteries with global interactions [47][48][49][50][51]. Recent publications [8,[32][33][34] also show the benefits of cooperative many-body effects in context of quantum heat engines, namely in Refs. [33,34] a direct link to Dicke superradiance [52] is made.…”

“…7(a) we present an example of how the energy levels evolve in the protocol given by Eqs. (31) and (32). The abrupt change of the ground state with t corresponds to a QPT which is crossed twice.…”

Stochastic thermodynamics of all-to-all interacting many-body systems

“…Models where such coarse grainings appeared can be found in Refs. [18,20,21]. α ,α such that current is directed to α w α α (λ)…”

“…However, little is known about their thermodynamic description. For instance, thermodynamics of nonequilibrium phase transitions started to be explored only recently [18][19][20][21][22][23][24][25][26][27][28][29][30]. There is a pressing need to develop methodologies to study thermodynamic quantities such as heat work and dissipation, not only at the average but also at the fluctuation level.…”

Cooperative many-body enhancement of quantum thermal machine power

“…In that context, starting with the seminal work by Scully et al [7], extensive investigations have focused on the question whether quantum coherence in either the machine's working medium [8][9][10][11][12][13] or the energising (hot) bath (the 'fuel') [14-24] could either boost the power output or the efficiency of quantum engines. Whilst these investigations have been mainly theoretical, impressive experimental progress has also been made such as the first realisation of a heat engine based on a single atom [25], the demonstration of quantum-thermodynamic effects in the operation of a heat engine implemented by an ensemble of nitrogen-vacancy (NV) centres in diamond [26] and the simulation of a quantum engine fuelled by a squeezed-thermal bath in a classical setting [27].Here we explore the possibility of exploiting collective (cooperative) many-body effects in quantum heat engines and refrigerators [28][29][30][31][32][33][34][35][36]. These generic quantum effects have a common origin with Dicke superradiance [37], whereby light emission is collectively enhanced by the interaction of N atoms with a common environment (bath) such that its intensity scales with N 2 [37-62].…”